In the first part of this series, I covered an introductory approach to mobile device security research using some of the same tools and techniques I've used over the years as a forensic investigator. At the end, I mentioned using mac-robber directly on Android and iOS devices followed by mactime to generate a timeline of the filesystem as a basic method of identifying system activity that can find mobile app vulnerabilities. I followed that up with how to get mac-robber compiled for Android, how to run it on an Android device, and how to process the resulting file into a timeline. Today, I'll be digging into how to do the same thing for iOS and detailing the extra hoops we have to jump through for iOS.
Warning: The following steps require a familiarity and comfort with using Linux or a similar Unix-based operating system, which you really and truly need if you're going to be analyzing iOS--a BSD-based operating.
First, you'll need a jailbroken iOS device. How to actually perform the jailbreaking and any jailbreaking-related issues are beyond the scope of this series, but there are plenty of resources on the Internet with detailed steps. The important part is that you must have root access on the device to use mac-robber.
Second, you'll need a way to get files onto your device. One of the first things I install after jailbreaking my device is an SSH server. It comes in handy for several reasons such as copying files using scp.
Where things deviate from the previous process we followed for Android is that we'll actually be compiling mac-robber on the iOS device. This requires we install a few necessary pre-requisites in addition to copying the actual mac-robber source code to the device. Note that I'm using aptitude to install some of the prerequisites and it must be installed using Cydia.
First, copy the mac-robber archive via SSH (or another method), and then, log into the device as root using SSH. Next, decompress the archive, change directories into the mac-robber folder, and run the following commands:
- aptitude install make automake ldid wget
- wget http://iphone-gcc-full.googlecode.com/files/libgcc.deb
- wget http://iphone-gcc-full.googlecode.com/files/headers-libs.deb
- dpkg -i libgcc.deb
- aptitude install iphone-gcc
- dpkg -i --force-overwrite headers-libs.deb
- gcc -o mac-robber mac-robber.c
The first command installs a few tools that are helpful for later tasks. The next three commands download some necessary pre-requisite libraries and install them. The fifth command actually installs GCC while the sixth installs some necessary C libraries and headers needed during compilation of certain C programs. The final command is where we finally compile mac-robber into an executable we can run on iOS.
I typically run mac-robber using SSH like so:
- ssh [email protected]_of_iOS_device "mac-robber /" > AttachmentOpen.body
The resulting file can then be processed into a timeline using mactime from the Sleuth Kit.
mactime -b AttachmentOpen.body > AttachmentOpen.timeline
At this point, you have the basics to start creating timelines of the iOS filesystem. In the next part, I'll cover some of the interesting things you can find and actual vulnerabilities you can uncover using timeline analysis.
John Sawyer is a Senior Security Analyst with InGuardians, Inc. The views and opinions expressed in this blog are his own and do not represent those of his employer. He can be reached at [email protected] and found on Twitter @johnhsawyer.